An analysis of histopathological features of Crohn’s disease in surgical specimens

Background The diagnosis of Crohn’s disease is challenging. This study aimed to compare the histological features of Crohn’s disease and non-Crohn’s disease (i.e., other intestinal inflammatory diseases) in surgical specimens to identify histologic features for differential diagnosis. Methods We evaluated patients who were diagnosed with Crohn’s disease (n = 171) and non-Crohn’s disease (n = 215) between 2010 and 2015 and underwent surgical bowel resection. The frequency of histological features in surgical resection specimens were compared between these two patient groups. Results Transmural inflammation, subserosal lymphoid aggregates, fissures or sinus-like structures, granulomas or granuloma-like nodules, abnormalities of the enteric nervous system, and mucosa structure alterations (i.e., muscularis mucosae thickening or mucosal atrophy with pseudopyloric gland metaplasia) were more frequent in Crohn’s disease than non-Crohn’s disease (p < 0.001 for all). A set of 3 of the above pathological features had a specificity of 93.5% for Crohn’s disease. Some of the above histologic features were further grouped as chronic inflammatory change that includes granulomas or granuloma-like nodules, lymphoid aggregates in the muscularis propria or subserosa, fissures or sinus-like structures, and architectural abnormality (i.e., the presence of abnormal enteric nervous system and/or mucosa structure alterations). A combination of transmural inflammation, chronic inflammatory change, and architectural abnormality had a sensitivity of 92.4% and a specificity of 97.7% for Crohn’s disease. Conclusions A combination of transmural inflammation, chronic inflammatory change, and architectural abnormality in surgical bowel resection specimens is diagnostic for Crohn’s disease.